This invention relates to improvements in cathode base plates for electrolytic refining.
According to conventional electrolytic refining methods, nonferrous metals have been obtained by electrodepositing a nonferrous metal onto a cathode base plate (which will be referred to as "base plate" hereinafter) installed within an electrolytic cell to thereby prepare a cathode plate with electrodeposited metal formed thereon (which will be referred to as "cathode plate" hereinafter). The electrodeposited metal plate (which will be referred to as the "metal plate") is then peeled off from the base plate by inserting a stripping means such as wedge, scraper, knife or the like between the base plate and the metal plate together constituting the cathode plate.
FIGS. 1 and 2 are side sectional views illustrating two exemplary cathode plate embodiments A' and A" according to the prior art. In the cases of cathode plates A' and A", automatic stripping apparatuses have usually been employed for the purpose of peeling off the metal plate 2' or 2" from the base plate 1' or 1" respectively.
With reference to the case of the cathode plate A', the stripping operation is carried out first by causing a mechanical impact or fluid impact at the ends 3' of the metal plates 2' respectively by means of a hammer or the like or by an air jet or the like, thereby forming fine voids in the border line between the base plate 1' and the metal plate 2', and then a stripping means (not shown) is inserted therethrough.
However, this cathode plate A' is noted to be defective in that said border line 7' is obscure because the edge portion 3', as is evident from the drawing, forms an acute angle with the base plate 1', and thus hinders insertion of the stripping means.
The cathode plate A" obtained by forming a narrow portion on a part of the side edge of the base plate 1", mounting a channel-shaped insulating material 4" thereon so as to cover both sides thereof, the thickness of said insulating material 4 being identical to that of the base plate 1" (as illustrated) or less than the thickness of the base plate 1", and electrodepositing the metal plates 2" thereon.
In this case, the stripping operation is carried out by forming fine voids in the border line 7" between the plates 1" and 2" in the same way as employed in the case of cathode plate A' and inserting the stripping means thereinto.
The cathode plate A", since its border line 7" is more distinct than that of the cathode plate A', can facilitate insertion of the stripping means, but on the other hand it is noted to be defective in that the insulating material 4" is liable to fall off the base plate 1" because of the impact caused during the transportation of the base plate 1", corrosion by electrolyte and the like, whereby the insertion of the stripping means is made still more difficult. It is thus required to mount a new insulating material 4 thereon again in order to successfully overcome the difficulty as aforesaid.